Semiconductor wafers having a thickness of less than 250 μm are particularly suitable for the formation of chip stacks in three-dimensional integration. During manufacture a thin semiconductor wafer is fastened to a carrier or handling wafer, which may be a thick semiconductor wafer. The handling wafer mechanically stabilizes the thin wafer to facilitate further process steps and is afterwards removed.
US 2005/0173064 A1 describes a method wherein a semiconductor wafer is mounted to a perforated carrier plate serving as a carrier. An adhesive layer is used to fasten the wafer. After the wafer has been thinned, the adhesive is dissolved with a solvent, which is introduced into the openings of the carrier plate. In this method the adhesive may be exposed to process chemicals that can adversely affect the bond stability. The handling of perforated carrier wafers requires tools like specially designed end effectors and involves a potential cross contamination risk.
WO 03/094224 A1 describes a method for producing a substrate. A layer is formed on a temporary support with a fragile bond created in the vicinity of the interface. The layer is then selectively and locally etched, and a second layer is bonded to cover the etched zones and to form essentially closed cavities distributed over the substrate. By the application of constraints the first layer is separated from its temporary support at the fragile bond.
US 2009/0218560 A1 describes methods for reversibly mounting a device wafer to a carrier by forming edge bonds, which are chemically and thermally resistant, but can also be softened, dissolved or mechanically disrupted to allow the wafers to be separated with very low forces and at or near room temperature at the appropriate stage in the fabrication process.
DE 101 56 465 C1 describes a method of producing a wafer arrangement including a bond connection. A wafer is provided with recesses in its first and second main surfaces in such a manner that the recesses penetrate the wafer. A high-temperature stable, detachable connection is formed between the wafer and a further wafer by means of a dielectric interlayer.
DE 100 55 763 A1 describes a method of producing a wafer connection. A wafer is provided with a liquid layer of alcohols and polymerized silicic acid molecules partially substituted by organic residues. The alcohols are partially vaporized to form a semi-solid sticky layer, which is joined to a further wafer. A heat treatment yields a high-temperature stable, removable connection between the wafers.
ZoneBond™, commercially available from Brewer Science Inc., provides temporary bonding and debonding at room temperature. The bonding is effected by an adhesive, which is removed by a solvent. Only a low separation force is required because the adhesive strength is reduced in the centre by a chemical modification of the carrier surface. At temperatures above ca. 350° C. the zone of reduced adhesion is destroyed and the wafer cannot be separated from the carrier any more.